Device and method in connection with the production of structures

ABSTRACT

Device in connection with the lithography of structures of nanometer size, which device comprises a first main part ( 1 ) with a first principally plane surface ( 2   a ) and a second main part ( 3 ) with a second principally plane surface ( 9   a ), said first surface and second surface being opposite to one another and being arranged in principle parallel in relation to one another, with an adjustable interval between them, and said first and second surface being arranged to form a support for a substrate ( 5 ) and a template ( 10 ) respectively, or vice-versa. According to the invention, said second main part ( 3 ) also comprises a cavity ( 6 ) for a medium, and means for adjusting a pressure of said medium, a wall of said cavity consisting of a flexible membrane ( 9 ), of which one side, which side faces away from the cavity ( 6 ), forms said second surface ( 9   a ). The invention also relates to a method that utilizes the device.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/SE00/02417 which has an Internationalfiling date of Dec. 4, 2000, which designated the United States ofAmerica.

TECHNICAL FIELD

The invention relates to a device in connection with the lithography ofstructures of nanometer size, which device comprises a first main partwith a first principally plane surface and a second main part with asecond principally plane surface, said first surface and second surfacebeing opposite to one another and arranged substantially parallel inrelation to one another, with an adjustable interval between them, andsaid first and second surface being arranged to provide support for asubstrate or template respectively, or vice versa. The invention alsorelates to a method in connection with the lithography of structures ofnanometer size. The invention is applicable in connection withnanoimprint lithography on semiconductor materials, such as silicon,indium phosphide or gallium arsenide, for the manufacture ofsemiconductor components, but also in connection with nanoimprintlithography on other rigid materials, such as ceramic materials, metalsor polymers with a relatively high glass transition temperature, for usein e.g. biosensors.

PRIOR ART

The trend in microelectronics is towards ever smaller dimensions. Inprinciple, development has been such that the dimensions are beinghalved every third year. Commercial components are now manufactured withstructures of roughly 200 nm in size, but there is a need to go evenfurther down in dimensions, to <100 mn. Research concerning componentsbased on quantum effects is now highly topical and a demand is beingcreated for a commercially applicable manufacturing technique forcomponents with dimensions <10 nm. These nanocomponents can be producedcurrently using serial technology in individual specimens, for researchpurposes, but for mass production a parallel production method isrequired. A parallel production method of this kind that has recentlybeen developed is nanoimprint lithography (NIL), U.S. Pat. No.5,772,905, which has set out the basic preconditions for the massproduction of structures close to atomic scale, see Stephen Y. Chou,Peter R. Krauss, Wei Zhang, Lingjie Guo and Lei Zhuang: “Sub-10 nmimprint lithography and application”, J. Vac. Sci. Technol. B, Vol. 15,No. 6, (1997). Several research reports have been presented on thesubject, but hitherto the method has been restricted to nanoimprintingon components with a small total area, typically only a few squarecentimeters, see Stephen Y. Chou, Peter R. Krauss and Preston J,Renstorm: “Nanoimprint lithography”, J. Vac. Sci. Technol. B. 14, 4129(1996); K. Pfeiffer, G. Bleidiessel, G. Gruetzner, H. Schulz, T.Hoffinann, H.-C. Scheer, C. M. Sotomayor Torres and J. Ahopelto:“Suitability of new polymer materials with adjustable glass temperaturefor nanoimprinting”, Proceeding of Micro- and Nano-EngineeringConference, (1998); and Leuven. Bo Cui, Wei Wu, Linshu Kong, Xiaoyun Sunand Stephen Y Chou: “Perpendicular quantized magnetic disks with 45Gbits on a 4×4 cm ² area”, J. Appl. Phys. 85, 5534 (1999).

However, no commercial equipment for NIL has yet been presented, whichis due in large part to the fact that an entirely new approach isrequired for the manufacture of nanometer-sized structures. Theproduction of such small dimensions puts considerably higher demandsthan before on all constituent process stages, new process materials,new designs and new technical solutions having to be developed. The needfor mass production of nanometer-size structures is great, however, andopens up entirely new possibilities for the design of more compactcircuits and sensors for various applications with considerably greatersensitivity than those of today.

The basic principle of NIL is mechanical deformation of a thin filmlayer, which is coated onto a plane plate of silicon. The NIL processcan be compared with the production process for CDs and can be describedin three stages:

-   1. Production of template: A template can be produced from various    materials, e.g. metal, semiconductor, ceramic or of certain    plastics. To create a three-dimensional structure on one surface of    the template, various lithographic methods can be used, depending on    the requirements for the size of the structure and its resolution.    E-beam and X-ray lithography are normally used for structure    dimensions that are less than 300 nm. Direct laser exposure and UV    lithography are used for larger structures.-   2. Imprint: A thin layer of a polymer, e.g. polyamide, is applied to    a plane substrate of silicon. The layer is heated and at a certain    temperature, the so-called imprint temperature, the predefined    template and substrate are pressed together, the inverse of the    template's structure being transferred in the polymer layer to the    substrate.-   3. Structure transfer: In the areas pressed together in the polymer    layer, a thin layer of polymer remains. The last stage is removal of    this thin remaining layer on the substrate. This is carried out in a    so-called “RIE” or oxygen plasma unit. The thinner this remaining    layer is, the finer the structures that can be created using the    nanoimprint process.

In the imprint stage (2) it is essential that the template and thesubstrate are arranged absolutely parallel in relation to one another.In known devices, however, there are a number of sources of error thatcause problems with a lack of parallelism. In some of the known devices,e.g. in the “Flip Chip” bonder, the parallelism between the surfaces istherefore measured, following which mechanical adjustment is undertakenusing special devices, e.g. piezoelectric components, to ensure that thesurfaces remain parallel in relation to one another. See AlbertoJaramillo-Nunez, Carlos Robledo-Sanchez, and AlejandroCornejo-Rodriguez: “Measuring the parallelism of transparent andnontransparent plates”, Optical Engineering—December 96-V. 35, Issue 12,pp. 3437–3441. This type of measurement and adjustment is complicated,however, and is in itself marred by sources of error, which obstructparallelism between the template and substrate.

Furthermore, there are structural variations in the material in thesurface of a plane plate, or in other words, on a nanometer scale, thereexists an unevenness in the surface of each plate (template andsubstrate), even if the plates are polished. These unevennesses lead toan undesirable uneven distribution of force over the surfaces when thetemplate and substrate are pressed together, which in turn results in anunevenly depressed structure on the substrate. This is particularlycritical for the imprint process if the plates are large, e.g. the sizeof the surfaces is more than 50 mm in diameter.

There are thus two main problems to solve for the commercial productionof nanometer-sized structures using the imprint technique. One problemis parallelization of the plane surfaces that are to be pressed togetherand the other problem is providing an even distribution of force overthe entire plane surface. Solving these problems is a prerequisite for acommercial process for nanoimprint lithography of materials forsemiconductor components on surfaces with total areas that are greaterthan approx. 7–20 cm².

BRIEF ACCOUNT OF THE INVENTION

The object of the present invention is to provide a device and method inconnection with the lithography of structures of nanometer size, bymeans of which device and method the above problems with regard toparallelism between the substrate and template, and an even distributionof force on compression, are solved. In particular, the device andmethod have been developed for nanoimprinting structures on materialsfor semiconductor components, which materials have total areas, normallycircular areas, which are greater than 7–20 cm², but can also be appliedfor nanoimprinting structures on other materials that have a certainrigidity, i.e. that are not flexible. Naturally, the invention can alsobe applied for nanoimprinting structures on materials that have smallertotal surfaces.

According to the invention, a device is thus presented according to thepreamble, characterized in that the second main part also comprises acavity for a medium, and means for adjusting a pressure of said medium,a wall of the cavity consisting of a flexible membrane, of which oneside, which side faces away from the cavity, forms the second surface.

The template is thus supported according to the invention by a flexiblemembrane, which membrane is pressurized on its opposite side, at thesame time as the substrate, or vice versa, is supported by a fixed andstable surface. With this, the substrate and template will be arrangedabsolutely parallel in relation to one another and at the same time thedistribution of force on pressing together the substrate and templatewill be absolutely even over the surfaces of the substrate/template. Theinvention thus builds, simply but brilliantly, on a utilization ofphysical principles, which eliminate the need for time-consuming, costlyand unreliable measuring and adjustment of the parallelism betweensubstrate and template.

According to one aspect of the invention, the membrane consists of aflexible material, preferably a polymer material or a thin metal, evenmore preferredly plastic, rubber or thin metal, the membrane having athickness of up to 10 mm, preferably up to 3 mm and even morepreferredly up to 1 mm. There is actually no lower limit to thethickness of the membrane, other than a practical one, in which case theultimate should be a membrane with a thickness that corresponds to asingle atom layer, which at least in the present situation is virtuallyimpossible. The membrane is best fixed in the case of the second mainpart around the periphery of the membrane, at the edges of the cavity,and otherwise deflectably.

According to another aspect of the invention, said medium consists of agas or a liquid with low compressibility, preferably an oil or even morepreferredly hydraulic oil. A simple oil such as e.g. brake fluid canalso be used. The cavity is intended to be filled hydraulically withsaid medium, the device also comprising means for adjusting the pressurein the cavity to 1–500 bar (excess pressure), preferably 1–200 bar, andeven more preferredly 1–100 bar during the actual imprint stage. Duringheating of the substrate, prior to the imprint stage, the pressure canbe adjusted here to 1–5 bar, and following heating, during the actualimprint stage, the pressure can be adjusted to 5–500 bar, preferably5–200 bar and even more preferredly 5–100 bar. Naturally, the pressurecan also be set to zero.

According to yet another aspect of the invention, the device alsocomprises means for heating, e.g. electrical or mechanical means, ormeans for irradiating, and means for cooling the substrate, e.g. bymeans of a cooling medium. Heating and cooling can be adjusted toachieve substrate temperatures typically of between 30 and 300° C.

With the device and the method according to the invention, well-definedstructures of nanometer size can be created on rigid materials withtotal areas that are greater than 7–20 cm², e.g. materials with amaximum width or diameter of up to 150, preferably 250 mm, even morepreferredly 350 mm or even larger, in a quick, easy and cheap manner. Acycle for nanoimprinting according to the invention typically takes lessthan four minutes, or less than 3 minutes, often around 2 minutes. Thenanometer-sized structures can here be down to below 100 nm inindividual structures, or below 50 nm, or even below 10 nm.

The invention is applicable to nanoimprint lithography on semiconductormaterials, such as silicon, for the manufacture of semiconductorcomponents. It has also been found surprisingly that nanoimprintlithography can be carried out by means of the invention on othersemiconductor materials such as e.g. indium phosphide (InP) or galliumarsenide (GaAs). These materials differ from silicon in that they areconsiderably more brittle and thus considerably more sensitive to unevenforce distribution on nanoimprinting. No other method or device has beenpresented previously that manages to carry out nanoimprinting on brittlesemiconductor materials such as indium phosphide and gallium arsenide.However, the present invention can also be applied in connection withnanoimprint lithography on other rigid materials, such as ceramicmaterials, metals or polymers with a relatively high glass transitiontemperature, for use in e.g. biosensors.

DESCRIPTION OF DRAWINGS

The invention will be described in greater detail below with referenceto the figures, of which:

FIG. 1 shows a first embodiment of a device according to the invention,seen from the side in cross-section,

FIG. 2 a shows a second embodiment of a device according to theinvention, seen from the side in cross-section, and how the first mainpart of the device can be displaced,

FIG. 2 b shows the embodiment according to FIG. 2 a in perspective,

FIGS. 3 a & 3 b show the device according to FIG. 1 or 2, on pressingtogether the substrate and template,

FIG. 4 shows a device according to the invention, seen from the side incross-section, including devices for heating and cooling the substrate,

FIG. 5 shows a front view of a device according to FIG. 4 for heatingthe substrate,

FIG. 6 shows a front view of a device according to FIG. 4 for coolingthe substrate,

FIG. 7 shows an alternative method of heating the substrate,

FIG. 8 a shows a side view in cross-section of a device for vacuumholding of the substrate or template,

FIG. 8 b shows a front view of the device in FIG. 8 a,

FIG. 9 a shows a front view of a second main part according to theinvention, comprising a device according to FIG. 8,

FIG. 9 b shows the device according to FIG. 9 a, seen from the side incross-section,

FIG. 10 a shows a front view of an alternative embodiment of a secondmain part according to the invention, comprising a device according toFIG. 8,

FIG. 10 b shows the device according to FIG. 10 a, seen from the side incross-section,

FIG. 11 a shows a front view of an alternative device for vacuum holdingof the substrate and template,

FIG. 11 b shows a side view in cross-section of the device according toFIG. 11 a,

FIG. 11 c shows the device according to FIG. 11 b, in side view incross-section with substrate and template thereon,

FIG. 12 a shows a side view in cross-section of yet another alternativedevice for vacuum holding of substrate and template,

FIG. 12 b shows the device according to FIG. 12 a, in side view incross-section with substrate and template thereon,

FIG. 13 shows a diagram of substrate temperature and pressure, as afunction of time, for a production cycle,

FIG. 14 a shows a scanning electron microscope picture of a template,

FIGS. 14 b–d shows scanning electron microscope pictures of variousnanometer-size structures achieved by means of the device and methodaccording to the invention.

Detail number 1 in FIG. 1 represents a first main part in a preferredembodiment of a device according to the invention. This first main part1 comprises a first principally plane base plate 2, which is preferablyarranged to be displaced in a direction that coincides with the normalfor its surface 2 a facing a second main part 3. A principally planesupport plate 4, on which support plate the substrate 5 is intended tobe placed, can be affixed to this surface 2 a. Alternatively, thesubstrate 5 can be placed directly onto the surface 2 a. The substrateconsists for example, according to the known technique for nanoimprintlithography, of a silicon plate with a thin layer of e.g. a polyamide,preferably polymethyl methacrylate (PMMA) on its surface 5 a facingtowards the second main part 3. The substrate 5 is preferably circular.The main parts 1 and 3 preferably also have a rotationally symmetricalappearance.

The second main part 3 has a cavity 6, which is formed by a bottom 7and, in the example shown, circular-cylindrical side walls 8. As a rooffor the cavity 6, a plane, flexible membrane 9 is arranged opposite thebottom 7. This membrane 9 consists in the example shown of a rubbermembrane, one side 9 a of which forms a support for the template 10, andhas a diameter or maximum width of 25–400 mm, preferably 50–350 mm. Themembrane has a thickness of up to 10 mm, preferably up to 3 mm and evenmore preferredly up to 1 mm. The template 10 consists, according to theknown technique for nanoimprint lithography, of a plate of e.g. metal,which is provided with a fine structural pattern, with dimensions innanometer size, on its surface 10 a facing towards the first main part1.

The membrane 9 is fixed on the second main part 3, around the peripheryof the membrane 9 at edges of the cavity 6, by means of a fixing device.A ring 11, which is circular in the example shown, is used as the fixingdevice, which ring is arranged to press firmly the peripheral edges ofthe membrane 9 between itself and the free edges of the side walls 8.Along its inner circular edge, on the side thereof that faces towardsthe membrane, the ring 11 is preferably bevelled 11 a, to provide a softdeflection for the membrane 9 on the transition from the ring 11. Therisk is hereby reduced of splits or fold notches in the membrane 9, itslife being extended.

The cavity 6 is intended to accommodate a medium, preferably hydraulicoil, which can be pressurized via an inlet channel 12, which can bearranged in the side walls 8 or in the bottom 7 of the cavity (as shownin FIG. 9 b). Pressurization takes place by means of a pump (not shown),which is best adapted to provide a pressure with very small variations.This can be achieved e.g. by means of a proportional valve.

Contained in the second main part 3 is also a second principally planebase plate 13, which forms a support for the part with the cavity 6.

FIG. 2 a shows a second embodiment of the device according to theinvention, a principally plane support plate 14 being arranged betweenthe membrane 9 and the template 10. The support plate 14 has a thicknessof 0.1–30 mm, preferably 0.1–20 mm, even more preferredly 0.1–10 mm, andmost preferredly 0.1–5 mm, and can be executed in materials such as ametal, a semiconductor material, or a ceramic material, e.g. stainlesssteel, silicon carbide or aluminium oxide. The above-mentioned supportplate 4 also best has these dimensions and is best executed in materialsof the same type.

The support plate 14 on the second main part 3 consists mostadvantageously of a material that is a good thermal insulator, i.e.which has low thermal conductivity.

The support plate 14 forms a fixing device for the template 10, which isexplained in greater detail in connection with FIG. 9. In thisembodiment, the ring 11 preferably has a spacer part 11 b and a lip 11 cthat prevents the support plate 14 from falling off the main part 3before both main parts are brought together, at least when the main part3 is arranged above the main part 1.

FIG. 2 a also shows, by means of arrows, how the main part 1 is arrangedto be displaced in relation to the main part 3 in a radial direction,i.e. in a direction that is parallel to the surfaces 2 a and 9 a of themain parts 1 and 3. The base plate 2 can here have a fixed part 2 bfacing away from the surface 2 a and a movable part 2. Displacement isexecuted in connection with the exchange of template and/or substrate.FIG. 2 b shows the embodiment according to FIG. 2 a in perspective.

FIGS. 3 a and b show the device according to FIG. 1 or 2 when thepressure in the cavity 6 has been increased so that the template 10 andsubstrate 5 are pressed together, thanks to the flexibility of themembrane 9, for transfer of the nanometer-sized structure on the surfaceof the template 10 a to the surface 5 a of the substrate.

FIG. 4 shows that the main part 1, for the substrate 5, can alsocomprise means 15 for heating the substrate, and means 16 for coolingthe substrate. In the preferred example shown, these means 15, 16 forheating and cooling respectively consist of support plates that arearranged between the substrate 5 and the base plate 2, preferably in theorder substrate 5, support plate 4 (with vacuum for holding thesubstrate), support plate 16 for cooling, support plate 15 for heating,and base plate 2. The support plate 15 for heating the substrate bestconsists of a material which has a good thermal insulation capacity,e.g. a ceramic material such as a ceramic insulator or a ceramiccomposite, e.g. macor. The support plate 16 for cooling the substratebest consists of a material that has good thermal conductivity, e.g.silicon carbide, stainless steel, aluminium or aluminium oxide in someform. The support plates 15 and 16 preferably have a thickness in thesame range as the support plate 14 according to the above.

FIG. 5 shows how the support plate 15 can contain an electric heatingcoil 17, which is inlaid in a groove in the surface of the support plate15. The heating coil/groove 17 is formed in the embodiment shown as adouble coil, but can of course have other shapes also. By analogy, thesupport plate 16, according to FIG. 6, can contain a channel 18 insidethe same for a cooling medium, e.g. a gas such as air, nitrogen orsomething else, or a cooling liquid such as water or something else. Thechannel 18 in the embodiment shown is formed as a double coil, but canof course also have other forms.

FIG. 7 shows an alternative embodiment, in which heating of thesubstrate 5 is carried out by means of irradiation R′ of the substratevia the base plate 2 and a support plate 4 or 16. The radiation R′ usedcan for example be of the IR radiation type (the support plate 16 bestbeing executed in silicon carbide) or radiation using radio frequencies,i.e. frequencies of 10 MHz and above, the device comprising means (notshown) for generating such radiation.

FIGS. 8 a and b show how the support plate 4 can be provided withdevices for vacuum holding of the substrate 5. The support plate herehas a groove 19 in both surfaces of the support plate 4, a circulargroove in the example shown. The two grooves 19 are joined to oneanother at one point 20 at least by a hole that is continuous throughthe plate 4. A vacuum is created in the groove 19 and hole 20 by aconnection (not shown) to a vacuum fan, via the base plate 2. By meansof this vacuum device the substrate 5 is sucked firmly onto the supportplate 4 and the support plate 4 in turn is sucked firmly onto thesupport plate 16 for cooling, or directly onto the base plate 2. It isto be perceived that also, or alternatively, the support plate 15 forheating and/or the support plate 16 for cooling can be provided withdevices for vacuum holding onto the support plate 4 and the base plate2.

FIGS. 9 a and 9 b show that the support plate 14 arranged in this casebetween the template 10 and the membrane 9 can also consist of a supportplate with a vacuum device 19, 20. Provided for the groove 19 and thehole 20, preferably directly connected to the hole 20, in this case is achannel 21 for connection to a vacuum fan (not shown). In this casealso, a bevelled part 11 a can be provided on the ring 11, which part 11a can lie between the membrane 9 and the vacuum support plate 14. FIG. 9a shows the support plate 14 without a template thereon, while FIG. 9 bshows a support plate 14 with a template thereon. It is also shown howthe inlet channel 12 can be arranged in the bottom of the main part 3,via the base plate 13.

The manufacturing cycle for nanoimprinting of a substrate 5 shall bedescribed below starting out from the figures. In the starting phase,both main parts 1 and 3 are displaced relative to one another in anaxial and radial direction, according to FIG. 2. The substrate 5 isplaced on the support plate 4 and the template 10 placed on the membrane9 or support plate 14. The substrate and template are best held in placeby means of a vacuum, but other methods are also conceivable. The firstmain part 1 is displaced in a radial direction into position in relationto the second main part 3, in order then to be displaced in an axialdirection towards the same. In that connection displacement is bestexecuted in an axial direction so that a small interval continues toremain of e.g. up to 10 mm, preferably up to 5 mm and even morepreferredly up to 1 mm, between the ring 11 and the support plate 4 orbase plate 2 if the support plate 4 is lacking This is shown in FIG. 3a. Alternatively, the axial displacement takes place so that the ring 11or its lip 11 c abuts the support plate 4 or base plate 2. This is shownin FIG. 3 b, the dimensions of the constituent components being adaptedso that there continues to remain a small interval, corresponding to theabove mentioned interval, between the substrate 5 and the template 10when the two main parts 1 and 3 come together.

Following the axial displacement of the main parts, the pressure of themedium in the cavity is increased via the inlet channel 12 to around 1–5bar so that the membrane 9 flexes out, a light pressing together of thesubstrate 5 and template 10 taking place. The substrate 5 is heated bymeans of a device for heating the same, e.g. according to FIG. 5 or 7,and then the pressure of the medium in the cavity 6 is increased to5–500 bar, preferably 5–200 bar, and even more preferredly 5–100 bar,via the inlet channel 12, the substrate 5 and the template 10 beingpressed together with a corresponding pressure, which pressure istransferred via the flexible membrane 9. Thanks to the flexiblemembrane, an absolutely even distribution of force is obtained over thewhole of the contact surface between the substrate and the template,these being made to arrange themselves absolutely parallel in relationto one another and the influence of irregularities in the surface of thesubstrate or template being eliminated. Following a compression timedepending on the choice of material, temperature, pressure etc., butwhich is typically less than 3 minutes, preferably less than 1 minute,cooling of the substrate commences by means of a device e.g. of the typeshown in FIG. 6. When cooling has been completed, the pressure in thecavity 6 is reduced and the two main parts 1 and 3 are separated fromone another, following which the substrate 5 and template 10 areseparated from one another. After this, the substrate is subjected tofurther treatment according to what is known for nanoimprintlithography. This further treatment is not a part of the presentinvention, and will not therefore be described in greater detail.

FIG. 10 a shows a support plate 14 without a template thereon, whileFIG. 10 b shows a support plate 14 with a template thereon. FIGS. 10 aand 10 b here show an alternative embodiment of the invention, in whichthe second main part 3 is formed as a periscopic part for the axialdisplacement of the same. Here the cavity 6 with its medium and related(not shown) pump is used also for the periscopic displacement Arrangedhere outside the side walls 8 are outer walls 22 with only a small gap23 between them. Arranged at the end of the side walls 8 and the outerwalls 22 respectively are sliding seals 24 a and 24 b respectively. Itis best if devices (not shown) are also provided to prevent the partwith the side walls 8 being displaced so far that it comes loose fromthe outer walls 22. The outer walls 22 are limited at the other ends bythe cavity's bottom 7 or base plate 13. The inlet channel 12 is arrangedin the outer walls 22, or in the bottom 7, 13, i.e. in the area outsidethe gap 23. Arranged in the area of the gap 23 is a second inlet channel25, by means of which the quantity of medium in the gap 23, and itspressure, can be influenced. The periscopic displacement of the mainpart 3, or rather of the membrane 9 and template 10 is achieved byincreasing the pressure in the cavity 6 via the inlet channel 12, at thesame time as the medium in the gap 23 is permitted to flow out via thesecond inlet channel 25. When the ring 11, or its lip 11 c, abuts thefirst main part 1 (not shown in FIG. 10), a continued increase in thepressure in the cavity will result in the membrane 9 translating thepressure to the template, so that this is pressed together with thesubstrate, as described above.

To retract the periscopic main part 3, following the completion ofimprinting, the pressure in the cavity 6 is released and the pressure inthe gap 23 increased instead via the second inlet channel 25. The sidewalls 8 are thereby displaced, and with them the membrane 9 and thetemplate 10, towards the base plate 13, the sliding seals 24 a and 24 bsliding against the outer walls 22 and the side walls 8 respectively.

FIGS. 11 a, b and c show an alternative device for vacuum holding of thesubstrate and template, which device consists of a support plate of thesame type as before, in connection with FIG. 1, named support plate 4,named 4′ in this figure. The support plate 4′ is provided, in the samemanner as shown in FIG. 8, with a groove 19 in both of its planesurfaces and a through hole 20, which runs below to a vacuum connection(not shown) to achieve a vacuum which holds the substrate 5 firmly onone surface of the support plate 4′ and holds the support plate 4′firmly on a base, e.g. a support plate for cooling the substrate 5, notshown in this figure. Arranged on one side only of the support plate 4′,outside the groove 19, is a second vacuum groove 26, in the exampleshown a circular groove 26 with a diameter that is greater than thediameter of the template 10 and the substrate 5. Provided for the groove26, at best via a hole 27, is a channel 28 for connection to a vacuumfan, not shown. The substrate 5 can be held firmly by means of thesupport plate 4′ by the first vacuum groove 19, the template 10 beingable to be placed directly onto the substrate 5, and following this, asshown in FIG. 11 c, a film or foil 29 e.g. of aluminium or rubber can beplaced completely covering or running around the periphery of thetemplate and substrate, which film or foil is sucked fast against thevacuum groove 26 and thereby holds the template 10 firmly against thesubstrate 5. Thanks to the device shown in FIG. 11, the substrate 5 andtemplate 10 can thus be placed together, as shown in FIG. 11 c, on onemain part 1, 3, of the device, following which the main parts aredisplaced in relation to one another, so that they are oriented over oneanother and close to one another, as described earlier. Following theimprint stage, the vacuum in the groove 19 can be released, while thevacuum in the groove 26 is maintained, the support plate 4′ being ableto be removed from the device with the template and substrate stillthere for a simple exchange of substrate.

FIGS. 12 a and b show yet another alternative device for vacuum holdingof the substrate and template, which device consists of a support plateof the same type as before, in connection with FIG. 1, named supportplate 4, in this figure named 4″. The support plate 4″ is provided, inthe same manner as shown in FIG. 8, with a groove 19 in both of itsplane surfaces and a through hole 20, which runs below to a vacuumconnection (not shown) to achieve a vacuum which holds the substrate 5firmly on one surface of the support plate 4′ and holds the supportplate 4′ firmly on a base, e.g. a support plate for cooling thesubstrate 5, not shown in this figure. Arranged in the support plate 4′is a raised edge 30 outside the groove 19 on one side of the supportplate, and a groove 31 in the angle between the edge 30 and the supportplate 4″, which groove 31 is connected to a vacuum channel 32. FIG. 12 ashows the support plate 4″ without a template and substrate thereon,while FIG. 12 b shows a support plate 4″ with a template 10 andsubstrate 5 thereon, inside the edge 30. The dimensions are adapted sothat there is only a small gap between the edge 30 and thesubstrate/template, through which gap air is sucked into the vacuumchannel 32. Both the template and substrate are hereby held firmly, thesame function as in FIG. 11 being able to be achieved. The edge 30 has aheight that exceeds the thickness of the substrate 5 (or the template 10if this is to be placed closest to the support plate 4″).

EXAMPLES

Imprint trials according to the invention were conducted according tothe following parameters: the substrate was 5.1 cm in diameter inSi/SiO₂, with a coating of 950 K PMMA which was oven-baked at 180° C.for 24 hours. The maximum pressure was 60 bar, max. temperature 170° C.and min. temperature 80° C. The template was 5.1 cm in diameter inSi/SiO₂, with template structures in the form of lines and dots withline widths of 50, 75, 100 and 150 nm, and diameters of 50 nm with adistance of 25 nm between the dots. The template was provided with aprotective layer of nickel with a thickness of 20 nm, which wasdeposited by vaporization. The template was cleaned before imprinting byimmersing it in acetone under the influence of ultrasound, and driedusing nitrogen gas.

FIG. 13 shows a diagram of substrate temperatures and pressures as afunction of time for the production cycle, which extended over a littlemore than 2 minutes in a device according to the invention. As shown inthe diagram, the time for the temperature increase was roughly 1 minute.Pressure was then loaded, via the membrane, and when the desired maximumpressure was reached, cooling of the substrate commenced. Duringcooling, the pressure was adjusted to the desired set point.

The trials showed that a pressure of around 60 bar gave an impression200 nm deep in the PMMA layer on the substrate. If greater depth isdesired, a higher pressure can be used.

Following 10 cycles with the same template, it could be confirmed thatthe entire surface of all substrates was evenly imprinted. Nosignificant variations in the structure could be observed in or betweenthe areas with different structure.

Around 50 nm PMMA remained in the impressions, which was removed byetching. Following etching, the profile on the surface of the substratehad near enough vertical walls. Following etching, the substrate wascoated in the impressions with Cr, by vaporization, and then a stage wasexecuted to remove the remaining PMMA, resulting in a successful metalcoating in the impressions.

FIG. 14 a shows a scanning electron microscope picture of a part of atemplate with lines/ recesses 100 nm wide and a gap distance of 300 nmbetween the lines. The total surface of the template was 25 cm². FIG. 14b shows a part of a substrate in which a layer of PMMA has beenimprinted with the template in FIG. 14 a, in a device according to theinvention. The structure arising is very regular and devoid of defects.

FIG. 14 c shows an aluminium-metallized surface of a substrate ofsilicon that has been imprinted in a device according to the invention,with lines of 100 nm, with 200 nm and 500 nm gap distances between thelines. In the picture shown, the imprinted surface has been metallizedwith aluminium and then PMMA has been removed. The total surface of thesubstrate was 25 cm².

FIG. 14 d shows aluminium dots of a size of 50 nm produced on a siliconsubstrate, by imprinting in PMMA in a device according to the invention.The dots have been made with varying gap distances on a total surface of25 cm². In the picture shown, the imprinted surface has been metallizedwith aluminium and the PMMA then removed. The minimum gap distance isjudged to be less than 25 nm.

The invention is not restricted to the embodiments and examplesdescribed above, but can be varied within the scope of the followingclaims. Thus it is easily perceived for example for the template andsubstrate to change places with one another in the figures shown. It isalso perceived that conventional measures in connection withnanoimprinting should be carried out, such as cleaning of the surfacesof the substrate and template, and the space between them, using pureparticle-free gas, e.g. nitrogen gas or another gas. Furthermore, it isperceived that the attachment of the membrane, formation of the cavityetc. can be executed in essentially different ways, without deviatingfrom the idea according to the invention due to this.

1. Device for nanoimprint lithography, which device comprises a firstmain part with a first principally plane surface and a second main partwith a second principally plane surface, said first surface and secondsurface being opposite to one another and being arranged in principleparallel in relation to one another, with an adjustable interval betweenthem, and said first surface being arranged to form a support for asubstrate and said second surface being arranged to form a support for atemplate or template assembly wherein said second main part alsocomprises a cavity for a medium, and means for adjusting a pressure ofsaid medium to a pressure within the range of 1–500 bar positivepressure, a wall of said cavity consisting of a flexible membrane, ofwhich one side, which side faces away from the cavity, forms said secondsurface entirely supporting said template or template assembly, saidtemplate or template assembly being supported only by said membrane andsaid pressure medium therebehind during nanoimprinting.
 2. Deviceaccording to claim 1, characterized in that said membrane (9) is fixedto the second main part (3) around the periphery of the membrane,preferably by means of a ring (11) which braces the membrane's peripheryagainst the second main part.
 3. Device according to claim 1 or 2,characterized in that the membrane (9) consists of a flexible material,preferably a polymer material or a thin metal, even more preferredlyplastic, rubber or thin metal, the membrane having a thickness of up to10 mm, preferably up to 3 mm and even more preferredly up to 1 mm. 4.Device according to claim 1, characterized in that said membrane (9) hasa maximum width, preferably a diameter, of 25–400 mm, preferably 50–350mm.
 5. Device according to claim 1, characterized in that said mediumconsists of a gas or a liquid of low compressibility, preferably an oiland even more preferredly hydraulic oil.
 6. Device according to claim 1,characterized in that said means for adjusting the pressure of saidmedium is arranged to adjust the pressure to a pressure within the rangeof 1–200 bar, preferably 1–100 bar.
 7. Device according to claim 1,characterized in that said first (2 a) and second (9 a) surface arearranged to be displaced in relation to one another in a direction whichcoincides with the normal for the surfaces, and preferably also in adirection which is parallel to the surfaces.
 8. Device according toclaim 7, characterized in that said second surface (9 a) is arranged tobe displaced periscopically towards said first surface (2 a), in adirection that coincides with the normal for the surfaces, said secondmain part (3) comprising a periscopically displaceable part (8, 9) whichis arranged to be displaced by means of adjusting the pressure of saidmedium.
 9. Method of nanoimprint lithography, hereafter termednanoimprinting, a substrate (5) and a template (10) being placed betweena first surface (2 a) and a second surface (9 a), which first and secondsurfaces are opposite to one another, principally plane and principallyparallel in relation to one another, characterized in that said secondsurface (9 a) consists of one side of a flexible membrane (9), apressure, of 1–500 bar positive pressure being created in a medium onthe other side of said membrane and lifting said template or saidsubstrate free from any support other than said membrane, so that thetemplate and substrate are pressed together, while said first surface (2a) acts as a dolly.
 10. Method according to claim 9, characterized inthat said first (2 a) and second (9 a) surface are first displacedtowards one another, before pressurization of the membrane's (9) otherside is executed.
 11. Method according to claim 9, characterized in thatsaid pressure, during compression, is adjusted to 5–500 bar, preferably5–200 bar and even more preferredly 5–100 bar.
 12. Method according toclaim 9, characterized in that said substrate (5) is first heated,electrically, mechanically or by irradiation, following which thetemplate (10) and substrate (5) are pressed together due to saidpressurization, that the substrate is then cooled, by means of a coolingmedium, following which the template and substrate are separated fromone another.
 13. Method according to claim 9, characterized in that acycle for nanoimprinting is executed in a time of less than 4 minutes,preferably 1–3 minutes.
 14. Device for nanoimprint lithography, whichdevice comprises a first main part (1) with a first principally planesurface (2 a) and a second main part (3) with a second principally planesurface (9 a), said first surface and second surface being opposite toone another and being arranged in principle parallel in relation to oneanother, with an adjustable interval between them, and said firstsurface (2 a) being arranged to form a support for a template (10) andsaid second surface being arranged to form a support for a substrate orsubstrate assembly wherein said second main part (3) also comprises acavity (6) for a medium, and means for adjusting a pressure of saidmedium to a pressure within the range of 1–500 bar positive pressure, awail of said cavity consisting of a flexible membrane (9), of which oneside, which side faces away from the cavity (6), forms said secondsurface (9 a), entirely and supporting said substrate or substrateassembly, said substrate or substrate assembly being supported only bysaid membrane and said pressure medium therebehind duringnanoimprinting.
 15. Device according to claim 14, characterized in thatsaid membrane (9) is fixed to the second main part (3) around theperiphery of the membrane, preferably by means of a ring (11) whichbraces the membrane's periphery against the second main part.
 16. Deviceaccording to claim 14, characterized in that the membrane (9) consistsof a flexible material, preferably a polymer material or a thin metal,even more preferredly plastic, rubber or thin metal, the membrane havinga thickness of up to 10 mm, preferably up to 3 mm and even morepreferably up to 1 mm.
 17. Device according to claim 14, characterizedin that said membrane (9) has a maximum width, preferably a diameter, of25–400 mm, preferably 50–350 mm.
 18. Device according to claim 14,characterized in that said medium consists of a gas or a liquid of lowcompressibility, preferably an oil and even more preferably hydraulicoil.
 19. Device according to claim 14, characterized in that said meansfor adjusting the pressure of said medium is arranged to adjust thepressure to a pressure within the range of 1–200 bar, preferably 1–100bar.
 20. Device according to claim 14, characterized in that said first(2 a) and second (9 a) surface are arranged to be displaced in relationto one another in a direction which coincides with the normal for thesurfaces, and preferably also in a direction which is parallel to thesurfaces.
 21. Device according to claim 20, characterized in that saidsecond surface (9 a) is arranged to be displaced periscopically towardssaid first surface (2 a), in a direction that coincides with the normalfor the surfaces, said second main part (3) comprising a periscopicallydisplaceable part (8, 9) which is arranged to be displaced by means ofadjusting the pressure of said medium.
 22. Device according to claim 1or 14, characterized in that at least one support plate (4, 4′, 4″, 14,15, 16) is arranged between said first (2 a) and/or second (9 a) surfaceand said substrate (5) or template (10), which support plate has athickness of 0.1–30 mm, preferably 0.1–20 mm, even more preferably0.1–10 mm and most preferably 0.1–5 mm.
 23. Device according to claim22, characterized in that said support plate (4, 4′, 4″, 14, 15, 16) isranged to be held firmly against said surface (2 a, 9 a), and/or 25against another support plate (4, 4′, 4″, 14, 15, 16) and/or againstsaid substrate (5) and/or template (10), by means of a vacuum, thedevice also comprising means (19, 20, 21, 26, 27, 28, 29, 30, 31, 32)for creating such a vacuum.
 24. Device according to claim 22,characterized in that one (16) of said at least one support plate haschannels (18) for a cooling medium.
 25. Device according to claim 22,characterized in that one (15) of said at least one support platesarranged to heat up electrically (17), mechanically or by irradiation(R′).